The invention relates to a safety device for a motor vehicle seat.
Safety devices of this type are known, for example, from the utility model DE 200 17 919 U1. They are suitable for a motor vehicle seat having a seat cushion part and a backrest. The backrest has a frame, a backrest cover, which faces rearward as seen in the direction of travel, and padding which faces forward, as seen in the direction of travel. An airbag module is integrated into the backrest and is arranged in that region of the backrest which faces the side wall structure of the motor vehicle. The airbag is deployed when there is an impact between a driver and the side wall structure of the motor vehicle, for example the B-pillar and/or the side door.
In the known safety device, the airbag module is arranged between the frame and the backrest cover, so that it is placed to the rear of the backrest cover and in front of the frame, as seen from the side wall structure. An airbag outlet opening is provided in the region in which the backrest cover and padding butt against each other. This known arrangement has the disadvantage that, if there is a side impact, structural parts penetrating the interior of the motor vehicle may jeopardize the interference-free emergence of the airbag. This situation may occur, for example, if the penetrating parts butt against the backrest cover and deform it, and the airbag outlet opening is thus concealed or the airbag module arranged to the rear of the backrest cover is damaged. Deformation of the backrest cover is possible, since the backrest cover serves to line the motor vehicle seat and is therefore not of sufficiently stable design.
Against this background, it is the object of the present invention to develop a safety device in such a manner that reliable and reproducible emergence of the airbag is ensured.
This object is achieved according to the invention by a safety device for a motor vehicle seat that includes a seat cushion part, a backrest having a frame, a backrest cover, which faces rearward as seen in the direction of travel, and padding which faces forward, as seen in the direction of travel. The safety device includes an airbag module that has an airbag, and the airbag module is integrated into the backrest and arranged in a region of the backrest which faces a side wall structure of the motor vehicle. The airbag module 11 is at least partially surrounded the frame 5 and is arranged to the rear of the frame 5 when looking from the side wall structure of the motor vehicle.
Accordingly, the invention is distinguished by the fact that the airbag module is arranged, as seen from the side wall structure, to the rear of the backrest frame—i.e. to the rear of its supporting part in the backrest. The effect of this arrangement is that the airbag module is shielded against forces acting from the direction of the side wall structure. In addition, an airbag outlet opening can be effectively protected against penetrating structural parts and it can therefore be ensured that the opening is always free for an airbag to emerge. The backrest frame is preferably designed in such a manner that virtually no deformation occurs. In the event of a lateral application of force, the entire backrest together with the seat cushion part is rather displaced in the direction of the center of the motor vehicle than the frame is lastingly deformed. A backrest frame of this type can consist, for example, of magnesium diecasting.
A further advantage of the invention can be seen in the fact that the construction is very simple because no additional measures are necessary in order to ensure that the airbag deploys reliably. On the contrary, existing parts of the backrest are used in order to bring this about. Accordingly, the arrangement according to the invention of the airbag module in the backrest ensures that the airbag is deployed or emerges considerably more reliably.
According to one embodiment, the airbag module has a housing which at least partially surrounds the airbag, for example in the rear region and in the side regions. Since the housing does not completely surround the airbag module, it therefore has a relatively wide opening. This means that the housing provides a relatively small resistance to the deploying airbag thus assisting a reliable deployment.
A plate can be provided in the region in which the housing does not surround the airbag module. This plate serves, on the one hand, to close the airbag housing and therefore to provide a certain protection in the inoperative state to the airbag components arranged in the housing. Furthermore, it serves to damp the first thrust of the deploying airbag, with the result that the airbag emerges at a moderate speed. Finally, the plate enables the airbag to emerge. When, during deployment, the airbag presses against the plate, the plate is bent up and pushes the backrest components, which join the plate, for example the padding, to the side. For this purpose, the plate is preferably arranged on that side of the frame which faces away from the outer contour of the seat that faces the side wall structure.
The plate can be connected on one side fixedly to the frame of the backrest. When the airbag emerges, this fixed connection forms a hinge about which the plate moves. However, it is also conceivable for the plate to be connected directly to the airbag housing and for it to be pivoted open from this connection.
The function of the plate may also be fulfilled by other components of the backrest. If, for example, the padding is arranged on a padding support, then it is conceivable for this padding support, which is likewise arranged between the padding and airbag module, to take over the closing, damping and opening.
According to a further embodiment, the frame at least partially surrounds the airbag module. The frame preferably surrounds the airbag module in the regions in which the housing surrounds the airbag. This arrangement enables the airbag to be protected in a particularly reliable manner against actions from the outside—in particular from the rear and from the side, as a result of which damage to the airbag module is prevented, ensuring an interference-free deployment of the airbag. This arrangement is therefore particularly advantageous because no additional elements are necessary in order to achieve this protection. The airbag is simply arranged in structures which are already present. In addition, the frame can serve as a guiding device by being aligned in such a manner that it predetermines the direction of deployment.
The outlet or the outlet opening for the airbag may be provided, for example, between the frame and padding. The material combination of a rigid frame and elastic padding, which are also coordinated with each other in terms of their shape, makes it possible for an outlet opening for an airbag to be provided in a particularly simple manner without the use of additional components. If the frame and padding are not connected to each other in the region of the outlet opening, the padding is deformed, during the deployment of the airbag, by the force which the airbag applies to it, and thereby releases the path for the emergence of the airbag. The arrangement according to the invention is visually attractive because the opening is not seen. In addition, neither seams nor other known closure elements are necessary. As a result, firstly, a simple and therefore also cost-effective solution is proposed. Secondly, elements which may obstruct the emergence of the airbag are not provided.
The outlet opening may be arranged, for example, in that region of the motor vehicle seat which faces the side wall structure. If the direction of deployment points obliquely forward, a particularly advantageous positioning of the airbag arises during the deployment and in the deployed state.